1. Field of the Invention
The present invention relates to broadband information transfer through optic fibers, and more specifically to a System and method for transferring much more information in optic fiber cables by significantly increasing the number of fibers per cable and/or by using multiple cores per each fiber, for example by using preferably flatter fibers, each with multiple hollow cores, each core preferably surrounded by smaller tunnels that create a light band-gap around each such core (which enables much better reflection). In order to enable this, the present invention solves various mechanical, optic and electronic problems that are created by stacking much more fibers in the same space.
2. Background
With the current explosion of information transfer, optic fibers are becoming faster all the time. Most of the recent advances in the amounts of data that these fibers can carry per time unit have come from adding more and more wavelengths (termed wavelengths) to the same fiber at the same time, a method which is called DWDM (Dense Wave Division Multiplexing). The biggest obstacle to this was the lack of suitable amplifiers, until the Erbium amplifiers were discovered in the late 80's, which have 2 advantages: 1. They don't need to convert the optical signals to electricity and back, but instead, light in the feeble input signals stimulates excited Erbium Atoms to emit more light at the same wavelength, 2. Because they preserve the wavelength of the optical signals, they can amplify many wavelengths simultaneously without having to first extract them separately and then recombine them after amplification. However, use of DWDM has been utilized only in the last few years. Today a single optic fiber can carry up to 80 or even 160 different wavelengths simultaneously, and the number is likely to increase further. The fastest bit-rates achieved so far per each wavelength are around 10 or 40 Gigabit per second, but it will be hard to go much beyond this, since higher bit-rates have much lower tolerance to dispersion problems. Therefore, the present wisdom concentrates mainly on trying to increase the number of wavelengths per fiber. The upper limit per optic fiber using the present methods is currently estimated to be around 100 terabits per second, and is expected to be achieved within the next 8 years.
However, The demand for broadband communications, fueled mainly by the Internet growth, is still growing by a much faster rate than the growth in the abilities of optic fibers. Typically, this demand has risen in the last few years by a factor of up to 5-fold each year, and this demand will probably continue to grow, as more people join and as users want to use heavier applications, such as for example Video, 3d, virtual reality, and so on. For example, many of the Trans-Atlantic submarine cables laid in the last few years were designed to satisfy demands for a number of years, but were fully used up (fully subscribed for) almost before their installations were finished. Trying to condense for example more wavelengths in each fiber is expensive and advances are not fast enough. On the other hand, other avenues for giant leaps have not been explored enough yet, and one of the things that can be tremendously improved almost instantly is the number of fibers per cable, a fact which the “current wisdom” seems to ignore at present. Typically, submarine cables each contain only 4-8 actual optic fiber pairs, or at most 16 pairs (in each pair one fiber typically transfers information in one direction and the other fiber in the other direction). This is a very small number and demonstrates some kind of myopia or fallacy in the prior art in this area. There are already about 300 such submarine cables around the world, and also a large number of land cables, so the current wisdom seems to be laying each time a cable with just a few optic fiber pairs, and then laying a new cable each time it is used-up. As will be shown below, this is very wasteful, apart from the fact that it is also less desirable ecologically (since submarine cables can damage for example coral on the sea floor, etc.). It is true that until the erbium amplifiers started to be used, adding more fibers to the cable was very expensive, because very expensive electro-optical repeaters were used, which converted the optic bits to electricity and after amplification back to optics. Each repeater station of this kind was able to handle only very few fibers, and adding more fibers would make it much more expensive. However, since the TAT-12/13 submarine cable (TAT stands for Trans-ATlantic), which entered service in 1996 and started using the Erbium amplifiers, this problem is now smaller. Yet, the “conventional wisdom” in this area has still not considered yet the possibility and implications of adding much more fibers per cable. Although there are indeed still problems involved in doing this even with Erbium and/or Raman amplifiers, the present invention tries to solve these problems in a very cost-effective way.